1. Field of the Invention
The present invention relates to methods used to reduce the amount of unwanted electronic mail (e-mail) received by a user of an e-mail service.
2. Related Art
The problem of unwanted, i.e. "junk," e-mail is well known and has received considerable attention. However, some background is thought to be of help in understanding the problem and the solutions that have been previously used or proposed, as well as the basic e-mail process. Referring to FIG. 1, there is shown the conventional process of sending e-mail messages from a source client 10 to a destination client 40. After the source client 10 composes an e-mail message, the message is sent from the source client 10 to a source simple mail transfer protocol (SMTP) server 20. The source SMTP server 20 sends the e-mail message to a destination SMTP server 30, which then sends the e-mail message to the destination client 40. A major drawback in the conventional process is the ever increasing amount of junk e-mail messages received by the destination clients 40. Such junk e-mail messages include advertisements for numerous goods and services. Users of e-mail systems have been spending an increasing amount of time separating their regular e-mail messages from unwanted e-mail messages.
Attempts have been made to reduce the number of junk e-mail messages received by the destination clients. Some methods require the source client to add descriptive information to the e-mail message so that the destination SMTP server can prevent undesired e-mail messages from being sent to the destination client. These methods are basically ineffective because the senders of junk e-mail messages will not add the descriptive information which will allow destination clients to block the junk e-mail messages.
Filter-out methods have also been developed. With such filter-out methods, a database of known sources (source clients) of junk e-mail messages is compiled. The destination SMTP server compares the source client's e-mail address to the e-mail addresses in the database and does not send undesired e-mail messages to the destination client. These methods have also proven to be ineffective because the development of robotic delivery programs. These robotic delivery programs send out thousands of junk e-mail messages and create nonexistent source client e-mail addresses. Thus, when one source client e-mail address is blocked, a new address is created. As a consequence, the database of known sources of junk e-mail messages can not keep up with changing e-mail addresses created by the robotic delivery programs.